OpenGL Programming Guide: The Official Guide to Learning OpenGL, Version 4.3, Eighth Edition

Using and Generating Mipmaps

Textured objects can be viewed, like any other objects in a scene, at different distances from the viewpoint. In a dynamic scene, as a textured object moves farther from the viewpoint, the ratio of pixels to texels in the texture becomes very low and the texture ends up being sampled at a very low rate. This has the effect of producing artifacts in the rendered image due to undersampling of the texture data. For example, to render a brick wall, you may use a large texture image (say 1024 × 1024 texels) when the wall is close to the viewer. But if the wall is moved farther away from the viewer until it appears on the screen as a single pixel, then the sampled texture may appear to change abruptly at certain transition ...